This book offers an extensive analysis of Woolf's engagement with science. It demonstrates that science is integral to the construction of identity in Woolf's novels of the 1930s and 1940s, and identifies a little-explored source for Woolf's scientific knowledge: BBC scientific radio broadcasts. By analyzing this unstudied primary material, it traces the application of scientific concepts to questions of identity and highlights a single concept that is shared across multiple disciplines in the modernist period: the idea that modern science undermined individualized conceptions of the self. It broadens our understanding of the relationship between modernism and radio, modernism and science, and demonstrates the importance of science to Woolf's later novels.